A conventional magnetic storage system typically includes a thin film magnetic head that includes a slider element and a magnetic read/write element. The head is coupled to a rotary actuator magnet and a voice coil assembly by a suspension and an actuator arm positioned over a surface of a spinning magnetic disk. In operation, a lift force is generated by the aerodynamic interaction between the magnetic head and the spinning magnetic disk, such that a predetermined flying height is maintained over a full radial stroke of the rotary actuator assembly above the surface of the spinning magnetic disk.
Some factors that limit writing (or recording) on a magnetic disk at high data transfer rates (or frequencies) using conventional magnetic heads at wide temperature ranges are the increasing requirements for higher magnetic fields and field gradients to achieve a smaller and smaller bit size. High magnetic fields are difficult to achieve particularly with narrow tracks and miniaturized heads and at low temperature. As a result, thin film magnetic heads incorporating a laser device have been developed and used in magnetic recording devices for heating the magnetic media to reduce the coercive force of the media during the write operation.
One example of a heat-assisted read/write head is shown in U.S. Pat. No. 6,016,290 entitled “Read/Write Head with Shifted Waveguide,” which is incorporated by reference herein. FIGS. 1 and 2 of the '290 patent, which are reproduced herein as FIGS. 1 and 2, illustrate an exemplary data storage system and head gimbal assembly, respectively, in which the instant invention may be utilized. More particularly, FIG. 1 illustrates a conventional disk drive 10 including a head stack assembly (HSA) 12 and a stack of spaced apart data storage disks (magnetic recording media) 14 that are rotatable about a common shaft 15. The head stack assembly 12 is rotatable about an actuator axis 16 in the direction indicated by arrow C. The head stack assembly 12 includes a number of actuator arms (18A, 18B, 18C), which extend into respective spaces between the disks 14. While only three actuator arms and disks are shown in FIG. 1, any desired number disks and actuator arms may be provided. The head stack assembly 12 further includes an E-shaped block 19 and a magnetic rotor 20 attached to the block 19 at an opposite position relative to the actuator arms. The rotor 20 cooperates with a stator (not shown) for rotating in an arc about the actuator axis 16. Energizing a coil of the rotor 20 with, for example, a direct current in one polarity causes rotation of the actuator arms about the actuator axis 16, thereby enabling the actuator arms to move across the disks 14.
A head gimbal assembly (HGA) 28 is secured to each of the actuator arms, as shown on actuator arm 18A in FIG. 1. Referring now more particularly to FIG. 2, the HGA 28 includes a suspension 33 and a read/write head 35. The suspension 33 includes a load beam 36 and a flexure 40 to which the read/write head 35 is secured. The read/write head 35 is comprised of a slider 47 secured to the free end of the load beam 36 by the flexure 40. Thus, the read/write element 50 is supported by the slider 47. In the example illustrated in FIG. 2, the read/write element 50 is secured to the trailing end 55 of the slider 47. The slider 47 may also be referred to as a support element since it supports the read/write element 50. The slider 47 can be any conventional or available slider.
In the exemplary device disclosed in the '290 patent, a laser diode 92 is secured to the slider 47 and is positioned over the read/write element 50 for optically coupling to a waveguide which passes through the read/write element. The laser beam propagating through the waveguide core heats a section of the track on the disk under the waveguide, thereby significantly reducing the disk coercivity. The magnetic field from the head at the medium adjacent a write gap is sufficiently large to reorient the domains of the data bits in the section of the track having reduced coercivity from the laser heating, thereby enabling the write element to write data within the track.
Further details regarding the structure and operation of the exemplary heat-assisted device shown in FIGS. 1 and 2 are provided in the '290 patent and, therefore, will not be further described in detail herein. While the heat-assisted device of the '290 patent, and other similar prior art devices, have improved the function of magnetic thin film heads in certain respects, further improvements in the structure and operation of such devices are still desired. Hence, the instant invention was developed in order to provide an improved heat-assisted thin film head for use in a magnetic hard disk drive.
U.S. Pat. No. 5,295,122 entitled “Flying Head of a Magneto-Optical Recording Apparatus” discloses a magneto-optical recording apparatus in which a thin film magneto-optical head is provided separately from the slider. FIGS. 13 and 14 of the '122 patent disclose the use of an optical integrated circuit that is connected to a light source using three optical fibers. One of the optical fibers is used for writing or reading and the other two are for outputting light that has been read. The optical integrated circuit includes branching and connecting circuits that are coupled, using an integrated mirror portion, with a light waveguide path shown in FIG. 14 of the '122 patent. In contrast to the instant invention, which is directed to magnetic recording apparatus, the '122 patent is limited to a magneto-optical recording apparatus. Thus, the '122 patent is not concerned with and does not contemplate heat-assisted writing in a magnetic recording apparatus. Moreover, the overall structure of the magneto-optical head with optical integrated circuit disclosed in the '122 patent has certain disadvantages with respect to the location and configuration of the optical integrated circuit. As a result, the teachings of the '122 patent are not readily adaptable to magnetic recording applications, much less magnetic recording applications that incorporate heat-assisted writing.